At the present time chickens and turkeys are commonly brought to a processing plant where they are butchered, defeathered, eviscerated, sorted and packaged for shipment in a chilled condition. More particularly, the birds are delivered in cages or coops to the plants by the growers, and in an automated plant the birds are manually removed from the coops and individually hung by the feet on a traveling conveyor which carries them through a series of processing stations. Typically, the birds are carried by this first conveyor through a stunning station, a killing station and a defeathering or picking station. The birds are then transferred to a second conveyor which carries them through an eviscerating station, where the birds are eviscerated, before delivering them to a chiller. Ordinarily, imperfect or damaged parts are removed from the birds before they are placed in the chiller or when removed from it. The birds remain in the chiller until the temperature thereof has stabilized at about 40.degree. F.
After being chilled, the birds are classified as to physical condition and placed on a third conveyor which carries them through one or more weighing stations and drops them according to size and grade at respective ones of a plurality of packing stations. At the packing stations the packers fill customer orders by selecting the desired number of a particular size and grade of bird and packing them in a box. The box is then weighed and if the total weight is too high or too low, the packer exchanges some of the packed birds for lighter or heavier ones as the situation requires.
By way of example, a typical customer specification might be fifty boxes each containing twenty-five grade A birds weighing between two and one-half or two and three-quarter pounds each and weighing a total of sixty-five pounds. The person doing the packing places a box on a scale and places in it twenty-five birds within the desired weight and grade range. The box may weigh anywhere between say sixty-two and sixty-eight pounds. The operator then substitutes smaller or larger birds within the desired weight range until the total weight is within a specified range of sixty-five pounds. The procedure is not only time consuming but generally results in substantially overweight boxes.
The sorting and packing operation is further complicated by the fact that the birds pick up a substantial amount of moisture during processing, and this moisture will be present at the weighing and packing station but will have evaporated by the time the birds reach the customer. This moisture thus constitutes a tare which must be predetermined and added to the weights of the individual birds and to the final boxes at the time of sorting and packing. Inasmuch as most of the moisture is picked up during chilling where the birds are usually immersed in cold water, the tare has generally been determined by periodically weighing a number of randomly selected birds before and after weighing and assuming that the average moisture pick-up of the selected birds is the same as the moisture pick-up for all of the birds being processed. The persons packing the boxes are thus required to make mental calculations of these tares and to subtract them from the weights appearing on the scales.
Most of the operations are thus carried out by persons who may or may not be highly efficient wherefor it is difficult to control unnecessary losses in such systems. This is of particular concern during the eviscerating process and during the final packing and weighing operations by which the billings are made. Moreover, it would be desirable to know the sizes of the live birds entering the plant so as to predetermine what sizes of birds will subsequently arrive at the packing station and which orders can be filled. This latter information is also useful in evaluating the growers who supply poultry to the plant.